Welcome to BYC. Could you post any pictures of what you are seeing? Ear infections can be common in chickens from mites, fungal, and bacterial infections. Lesions inside the mouth are common with diptheretic or wet fowl pox and canker (trichomoniaisis.) What color are the blisters? Here are some good links to read with pictures of both wet pox and canker:
Canker is a condition mostly associated with pigeons and is caused by a tiny parasite called trichomonas. This parasite is often spread through contaminated drinking water. The parasite causes a ‘yellow button’ of pus to form in your bird’s mouth. This can stop your bird from eating normally leading to weight loss.
What to look for
- Weight loss
- Birds picking up food then dropping it
- A cheese-like plaque in your birds mouth (see photo)
- A reluctance to eat
Treating canker or suspected canker is a job for a vet who will likely prescribe an anti-parasitic medication.
Ensure that your birds' drinking water is changed daily. Try to keep the drinkers in the chicken house to discourage wild birds from sharing your birds’ water.